RTAI/RtLinux
Normally I am not subscribed to the kernel list, but after a msg from Karim that there was a "fight" going on about RTAI I read the archives and decided that it was important enough to join the discussion.
Both Linus and Larry seem to be not very interested in hard-realtime Linux additions, this is OK. I mean everybody has his interests and with so many Linux users and developers you can't all focus on the same thing.
But we (RTAI developers, which include Karim and myself) have decided to focus on hard-realtime extensions to Linux. And it is than always very motivating to hear nobody gives a f*ck about your work or problems, because "hey, you don't have a business model that makes sense anyway"
For example, first there is said that there is no userspace hard-realtime, than Karim corrects that, than there is said that a userspace program that uses mlockall is actually a module: with other words be quiet and go sit in the corner.
This seems the same as what happened with FSMLabs, first they explain why userspace hard-realtime is crap, and now they have implemented it them self and explain how good it is.
We have had several discussions with FSMLabs about userspace hard-realtime and asked for comments on for example the following situation.
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When i write a RTAI module, that changes the sched_setparam in such a way that SCHED_FIFO and SCHED_RR are now hardrealtime. Than a binary program that runs on a computer with the RTAI kernel-module loaded violates the patent, and on a computer that doesn't have it loaded it doesn't violate the patent.
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needless to say we never even got a reply on questions like these. When you have to believe FSMLabbs, you are not allowed to use non-GPL software on a system that has a RTAI module loaded, according to Eben Mo
There was also asked about the possibility (and even some person on the RTAI list started such a project) to have a *BSD version of RTAI, well the answer is simply NO. since *BSD will not accept GPL kernel code, and the RTLinux patent doesn't allow no GPL implementations there will be no free *BSD with this type of hard-realtime. Of course you can buy the FSMLab version, but than you can just as well buy a true RTOS, like VxWorks.
Also apparently there is the idea that all RTAI developers want to become rich by getting the patent out of the way and sell RTAI. I know you all know this is simply not true, like most Linux hacker we spend a large part of our free time to give the real-time community a usable piece of software where they normally have to pay for.
So please don't stamp us as some money sucking bastards that shouldn't be allowed to use Linux in the first place.
I just hope the linux developers are smart enough to not accept the RTLinux into the main kernel, cause someday someone might come up with the idea to write something that allows to have userspace programs to be hard-realtime, and than you have to stop allowing non GPL userspace programs, like for example GLIB( which is LGPL).
- Erwin Rol , RTAI Developer
Quoted 26 lines · Erwin Rol
Normally I am not subscribed to the kernel list, but after a msg from Karim that there was a "fight" going on about RTAI I read the archives and decided that it was important enough to join the discussion.
Both Linus and Larry seem to be not very interested in hard-realtime Linux additions, this is OK. I mean everybody has his interests and with so many Linux users and developers you can't all focus on the same thing.
But we (RTAI developers, which include Karim and myself) have decided to focus on hard-realtime extensions to Linux. And it is than always very motivating to hear nobody gives a f*ck about your work or problems, because "hey, you don't have a business model that makes sense anyway"
For example, first there is said that there is no userspace hard-realtime, than Karim corrects that, than there is said that a userspace program that uses mlockall is actually a module: with other words be quiet and go sit in the corner.
This seems the same as what happened with FSMLabs, first they explain why userspace hard-realtime is crap, and now they have implemented it them self and explain how good it is.We have had several discussions with FSMLabs about userspace hard-realtime and asked for comments on for example the following situation.
Quoted 10 lines
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When i write a RTAI module, that changes thesched_setparamin such a way thatSCHED_FIFOandSCHED_RRare now hardrealtime. Than a binary program that runs on a computer with the RTAI kernel-module loaded violates the patent, and on a computer that doesn't have it loaded it doesn't violate the patent.
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needless to say we never even got a reply on questions like these. When you have to believe FSMLabbs, you are not allowed to use non-GPL software on a system that has a RTAI module loaded, according to Eben Mo
Some how a small piece of the mail is missing here.
... according to Eben Moglen this can't be correct.
- Erwin
Quoted 29 lines
There was also asked about the possibility (and even some person on the RTAI list started such a project) to have a *BSD version of RTAI, well the answer is simply NO. since *BSD will not accept GPL kernel code, and the RTLinux patent doesn't allow no GPL implementations there will be no free *BSD with this type of hard-realtime. Of course you can buy the FSMLab version, but than you can just as well buy a true RTOS, like VxWorks.
Also apparently there is the idea that all RTAI developers want to become rich by getting the patent out of the way and sell RTAI. I know you all know this is simply not true, like most Linux hacker we spend a large part of our free time to give the real-time community a usable piece of software where they normally have to pay for.
So please don't stamp us as some money sucking bastards that shouldn't be allowed to use Linux in the first place.I just hope the linux developers are smart enough to not accept the RTLinux into the main kernel, cause someday someone might come up with the idea to write something that allows to have userspace programs to be hard-realtime, and than you have to stop allowing non GPL userspace programs, like for example GLIB( which is LGPL).
- Erwin Rol , RTAI Developer
Quoted 5 lines · Erwin Rol
I just hope the linux developers are smart enough to not accept the RTLinux into the main kernel, cause someday someone might come up with the idea to write something that allows to have userspace programs to be hard-realtime, and than you have to stop allowing non GPL userspace programs, like for example GLIB( which is LGPL).
LGPL can be used as GPL. If you haven't even read the license do that before the flamewar please.
The RtLinux patent seems to boil down to "If you are free software we are free software, if you are proprietary we play in your space too, please pay up". Its not something I'm totally happy with but I don't really see how else Victor can phrase it.
Hello Alan, and the others,
First of all my mail was not meant to be a flame, if it looked like that I apologize for that.
Quoted 7 lines · Alan Cox
Quoted 5 lines · Erwin Rol
I just hope the linux developers are smart enough to not accept the RTLinux into the main kernel, cause someday someone might come up with the idea to write something that allows to have userspace programs to be hard-realtime, and than you have to stop allowing non GPL userspace programs, like for example GLIB( which is LGPL).
GLIB should have been GLIBC, but that doesn't really mather for the discussion.
Quoted 3 lines
LGPL can be used as GPL. If you haven't even read the license do that before the flamewar please.
I know this, the point is that when you use the LGPL to be used as the GPL it is not really LGPL anymore. A binary program using GLIBC depends on the fact that GLIBC allows that (because of its LGPL license). What i wanted to say is that "allowance" might be taken away by the patent license.
Quoted 5 lines
The RtLinux patent seems to boil down to "If you are free software we are free software, if you are proprietary we play in your space too, please pay up". Its not something I'm totally happy with but I don't really see how else Victor can phrase it.
IANAL, so i would not know how to phrase it. Thats why I (and several others) asked FSMLabs to explain some of it in more clear language, and we gave some examples (like the one in my other mail) so FSMLabs could say if those where compliant with their license or not.
The big question still is where the patent "stops", and there ppl like Eben Moglen and Victor Yodaiken have very different opinions. A lot of other ppl try to explain how they see things, and of course those explanations also differ a lot, but that is just normal.
It is like a patent on VM management, or some other kernel internal technique, does that mean that that patent is also has something to say about ppl that write programs for that OS ? The same with LXRT (the userspace part of RTAI), its implementation might fall under the patent, but does the program that uses the LXRT services also fall under the patent ? Than the next question , the userspace<->kernel border is nothing "magical" in respect to patent law, so for kernel modules the same question is true; do they implement the patent (and hence should they comply to the license) or do they just use the services the patented part offers.
I hope you can see that these are uncertainties that I (and other ppl have) and would just liked the have cleared up without a lawsuit :-/ Even FSMLabs, and their users would provide from that, cause more ppl can program more in a shorter time :-)
- Erwin
Quoted 10 lines
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LGPL can be used as GPL. If you haven't even read the license do that before the flamewar please.
I know this, the point is that when you use the LGPL to be used as the GPL it is not really LGPL anymore. A binary program using GLIBC depends on the fact that GLIBC allows that (because of its LGPL license). What i wanted to say is that "allowance" might be taken away by the patent license.
The basic problem is again that some people want to have the privileges of GPL without the responsibilities of GPL. That is a very old debate and I don't think it is sensible to krank it through again. Do GPL work and you can use the services of the comunity, do non-GPL and you need to get these services under other terms. I realy don't see whats so wrong unfair and evil about this.
Quoted 6 lines
It is like a patent on VM management, or some other kernel internal technique, does that mean that that patent is also has something to say about ppl that write programs for that OS ? The same with LXRT (the userspace part of RTAI), its implementation might fall under the patent, but does the program that uses the LXRT services also fall under the patent ?
The question of derived work is realy exhaustively discused and there are plenty of statements on this including statements by the FSF itselfe. mere agregation of work does not put you under any copywrite restrictions, derived work does - drawing this line is not easy and expecting anybody to give you "the definitive guide on derived work" is a bit naiv. You might want to scan the FSF statements on these issues...
hofrat
Quoted 11 lines · Der Herr Hofrat
Quoted 10 lines
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LGPL can be used as GPL. If you haven't even read the license do that before the flamewar please.
I know this, the point is that when you use the LGPL to be used as the GPL it is not really LGPL anymore. A binary program using GLIBC depends on the fact that GLIBC allows that (because of its LGPL license). What i wanted to say is that "allowance" might be taken away by the patent license.
Quoted 6 lines
The basic problem is again that some people want to have the privileges of GPL without the responsibilities of GPL. That is a very old debate and I don't think it is sensible to krank it through again. Do GPL work and you can use the services of the comunity, do non-GPL and you need to get these services under other terms. I realy don't see whats so wrong unfair and evil about this.
The "serice" in this cause is not sourcecode, or an other product, it is an idea. I totally agree with you that when you want to derive from GPL software you should comply with its license. This is not about deriving software, this is about the use of an idea, which happens to be made into a patent (by a patent office with a very questionable reputation, also in this case as lots of ppl pointed out before).
Quoted 8 lines
Quoted 7 lines
It is like a patent on VM management, or some other kernel internal technique, does that mean that that patent is also has something to say about ppl that write programs for that OS ? The same with LXRT (the userspace part of RTAI), its implementation might fall under the patent, but does the program that uses the LXRT services also fall under the patent ?
Quoted 6 lines
The question of derived work is realy exhaustively discused and there are plenty of statements on this including statements by the FSF itselfe. mere agregation of work does not put you under any copywrite restrictions, derived work does - drawing this line is not easy and expecting anybody to give you "the definitive guide on derived work" is a bit naiv. You might want to scan the FSF statements on these issues...
Those statements are mostly valid for copyright cases, where i derive a piece of software from a other piece of software. These are very hard to map to patent cases like this one is. Cause if this was about deriving software, RTAI developers would have no problem with FSMLabs at all, cause we write our own software or we comply to the license of the software we use (keep in mind that RTAI was LGPL, and is now GPL, so RTAI itself is in no way colliding with the GPL). It is about users of RTAI that might want to keep their program non-GPL, and the question is, are they allowed to. Since they are not deriving from RTAI (they just use the services it offers) they are free to do so, when it would be a simple copyright case, but FSMLabs thinks different on this point. So thats what this is all about, where does the patent "stop" ? that question was always pushed into the copyright corner, and never answered correctly, apart by Eben Moglen, who apparently is not qualified enough to say anything on this topic (when i have to believe some ppl).
- Erwin
Quoted 2 lines
hofrat
Quoted 2 lines · Erwin Rol
Both Linus and Larry seem to be not very interested in hard-realtime Linux additions, this is OK.
I'm interested in hard realtime. I'm extremely uninterested in changes to the mainline source base in order to get them. That's exactly why I like the RT/Linux approach so much, it is the least invasive to the kernel and - surprise - also has the best performance.
If people were to learn that real time and multi-user throughput are by definition mutually exclusive, I'd be a lot happier. As it is, we have the SGI/Montevista crowd cramming their stuff into the kernel and each "little" thing makes the kernel a less pleasant place to be and brings it one step closer to the point when it gets abandoned like ever other OS in the history of our field.
Quoted 2 lines
Also apparently there is the idea that all RTAI developers want to become rich by getting the patent out of the way and sell RTAI.
So the thing I have a problem with is that Victor says that all GPL is fine. You say you are all GPL. So far, no problem. Yet you keep coming back and saying there is a problem, that Linux is going to be out of the running as a real time platform because of the patent. I don't get it, why should the patent prevent Linux from being used? All it does is say "if you aren't making money, we aren't making money, if you are making money, we want a cut". That seems OK to me, in fact, it seems more than OK. It seems like someone who is trying to help those who are helping others and charge those who are charging others. That's smart, that's good. It means that FSMlabs will be here 20 years from now, still supporting this stuff, whereas all the "we'll survive off of support" people will have long since gone under.
Signature · 2 lines
--- Larry McVoy lm at bitmover.com http://www.bitmover.com/lm
Quoted 9 lines · Larry McVoy
Quoted 2 lines · Erwin Rol
Both Linus and Larry seem to be not very interested in hard-realtime Linux additions, this is OK.
I'm interested in hard realtime. I'm extremely uninterested in changes to the mainline source base in order to get them. That's exactly why I like the RT/Linux approach so much, it is the least invasive to the kernel and - surprise - also has the best performance.
If you take a look at RTAI's history you will see that RTAI has been using a HAL and a very small kernel patch long before RTLinux started using that.
Quoted 10 lines
If people were to learn that real time and multi-user throughput are by definition mutually exclusive, I'd be a lot happier. As it is, we have the SGI/Montevista crowd cramming their stuff into the kernel and each "little" thing makes the kernel a less pleasant place to be and brings it one step closer to the point when it gets abandoned like ever other OS in the history of our field.
Quoted 2 lines
Also apparently there is the idea that all RTAI developers want to become rich by getting the patent out of the way and sell RTAI.
Quoted 12 lines
So the thing I have a problem with is that Victor says that all GPL is fine. You say you are all GPL. So far, no problem. Yet you keep coming back and saying there is a problem, that Linux is going to be out of the running as a real time platform because of the patent. I don't get it, why should the patent prevent Linux from being used? All it does is say "if you aren't making money, we aren't making money, if you are making money, we want a cut". That seems OK to me, in fact, it seems more than OK. It seems like someone who is trying to help those who are helping others and charge those who are charging others. That's smart, that's good. It means that FSMlabs will be here 20 years from now, still supporting this stuff, whereas all the "we'll survive off of support" people will have long since gone under.
It is not so OK if you keep in mind that this "if you make money, we want a part of it" is backed by a questionable patent. And if FSMLAbs still will be there in 20 years is not something you or I can predict, they might be bought by some large embedded firm tomorrow and the patent with it, and as far as i understand the patent license this means it is void when that happens.
- Erwin
Quoted 3 lines
Signature · 2 lines
--- Larry McVoy lm at bitmover.com http://www.bitmover.com/lm
On Sat, 25 May 2002, Larry McVoy wrote:
| On Sat, May 25, 2002 at 11:05:32AM +0200, Erwin Rol wrote: | > Both Linus and Larry seem to be not very interested in hard-realtime | > Linux additions, this is OK. | | I'm interested in hard realtime. I'm extremely uninterested in changes | to the mainline source base in order to get them. That's exactly why | I like the RT/Linux approach so much, it is the least invasive to the | kernel and - surprise - also has the best performance. | | If people were to learn that real time and multi-user throughput are | by definition mutually exclusive, I'd be a lot happier. As it is, | we have the SGI/Montevista crowd cramming their stuff into the kernel
In this example, SGI and MV are at opposite ends of the spectrum, right? High-end servers vs. embedded (and maybe RT).
I expect that most of the continued growth of Linux will be in these 2 areas (servers and embedded) -- but we can't just abondon the desktop/workstation space either.
Having 1 person say that Linux has problems in the embedded space doesn't carry much weight with me, but having 2-3 other people confirm it does start to concern me.
| and each "little" thing makes the kernel a less pleasant place to be | and brings it one step closer to the point when it gets abandoned | like ever other OS in the history of our field.
What I'd like to see/hear is a discussion about how to accommodate all of these OS spaces (servers, workstations, mobile, embedded) without making Linux ugly (or uglier in a few cases). Maybe a good topic for discussion in Canada... in a hallway or a bar or a BOF.
Maybe the embedded/RT space is always maintained outside of the kernel.org kernel tree; I don't know.
But certainly parts of the high-end server space want to be included in the mainstream kernel.org tree.
Sorry about adding something non-legal to the discussion. Not.
Signature · 1 line
~Randy
In message <[email protected]>
Quoted 4 lines · Randy Dunlap
Having 1 person say that Linux has problems in the embedded space doesn't carry much weight with me, but having 2-3 other people confirm it does start to concern me.
OK, so let's add another confirmation - mine. Just $0.02, of course.
Wolfgang Denk
Signature · 3 lines
Software Engineering: Embedded and Realtime Systems, Embedded Linux Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: [email protected] The best things in life are for a fee.
...
Quoted 3 lines
I expect that most of the continued growth of Linux will be in these 2 areas (servers and embedded) -- but we can't just abondon the desktop/workstation space either.
Does any have clue on the Linux pick-up in schools
- in Mexico?
- in China?
- in India?
Eric
On Sat, 25 May 2002, Eric Brunner-Williams in Portland Maine wrote:
| > I expect that most of the continued growth of Linux will be | > in these 2 areas (servers and embedded) -- but we can't just | > abondon the desktop/workstation space either.
I didn't mean to suggest that we would abandon the desktop space. If I did, sorry about that.
| Does any have clue on the Linux pick-up in schools | - in Mexico? | - in China? | - in India?
Yes, some clue.
And even in Portland, Oregon, with school districts fighting an M$ audit. (old news, a few weeks old)
Signature · 1 line
~Randy
Quoted 10 lines · Larry McVoy
Quoted 2 lines
Also apparently there is the idea that all RTAI developers want to become rich by getting the patent out of the way and sell RTAI.
So the thing I have a problem with is that Victor says that all GPL is fine. You say you are all GPL. So far, no problem. Yet you keep coming back and saying there is a problem, that Linux is going to be out of the running as a real time platform because of the patent. I don't get it, why should the patent prevent Linux from being used? All it does is say "if you aren't making money, we aren't making money, if you are making money, we want a cut".
That's the whole point isn't it. If Linus had used a licensing model (patent or copyright, I don't care) by which every Linux user would have to pay him a royalty, we wouldn't be here today. The same stands for real-time in Linux. As long as users have to pay one vendor every time they use the technology, it will not lift off the ground and will keep Linux stuck with it.
Quoted 4 lines
That seems OK to me, in fact,
it seems more than OK. It seems like someone who is trying to help those who are helping others and charge those who are charging others. That's smart, that's good.
This is an oversimplification. You should add that Victor wants to be the only one who can help others. And in doing so, he is not helping anyone but himself.
Quoted 3 lines
It means that FSMlabs will be here 20 years
from now, still supporting this stuff, whereas all the "we'll survive off of support" people will have long since gone under.
I personnally think that FSMLabs will probably not live very long. They base their entire business model on one very shallow patent. The day the patent goes, so does FSMLabs.
It's not like this is IBM who has thousands of patents. This company relies on a single shallow patent for its entire revenue stream. Talk about playing Russian-roulette with a fully loaded gun.
Karim
===================================================
Karim Yaghmour
[email protected]
Embedded and Real-Time Linux Expert
===================================================
Quoted 5 lines · Larry McVoy
So the thing I have a problem with is that Victor says that all GPL is fine. You say you are all GPL. So far, no problem. Yet you keep coming back and saying there is a problem, that Linux is going to be out of the running as a real time platform because of the patent. I don't get it, why should the patent prevent Linux from being used?
The problem is with a non-GPL userspace.
Using an analogy, consider what would occur if a company revealed it had a patent on some key part of the Linux dcache - a patent free for all GPL users, but requiring a license for any commercial code. In theory this isn't a problem, but what happens when that company starts demanding licensing fees from application developers like Oracle, IBM, and even BitKeeper Inc? What if the patent holder was Rational Inc and they were not eager to license the patent to some companies? Finally consider what would happen if there were a dozen (hundreds?) of patent owners demanding royalties for a userspace application.
To be clear, I do not believe this is the case with RTAI. Their userspace appears to be distinctly different from Linux userspace. But I hope you can appreciate why this concept can be very disturbing.
-Kevin
Signature · 4 lines
------------------------------------------------------------------------ | Kevin O'Connor "BTW, IMHO we need a FAQ for | | [email protected] 'IMHO', 'FAQ', 'BTW', etc. !" | ------------------------------------------------------------------------
Quoted 4 lines · Kevin O'Connor
Using an analogy, consider what would occur if a company revealed it had a patent on some key part of the Linux dcache - a patent free for all GPL users, but requiring a license for any commercial code. In theory this isn't a problem
Oh, yes it is. GPL and commercial DO NOT COVER EVERYTHING, damnit. And I don't fscking care for Oracle, IBM, etc. - there are folks doing stuff under other free licenses and I find casual dismissing them from consideration disgusting at extreme. Especially if you take care to count the amounts of good ideas that came from, say it, CSRG folks and from Oracle. Good ideas we are using. Shame...
Quoted 7 lines · Kevin O'Connor
Using an analogy, consider what would occur if a company revealed it had a patent on some key part of the Linux dcache - a patent free for all GPL users, but requiring a license for any commercial code. In theory this isn't a problem, but what happens when that company starts demanding licensing fees from application developers like Oracle, IBM, and even BitKeeper Inc? What if the patent holder was Rational Inc and they were not eager to license the patent to some companies?
If you think that we don't worry about this, you're wrong. That's why we write our own code here and don't depend on outside code, and it's also why we are constantly spending time in the patent database. We've made changes to BK to avoid Rational patents. Actually, that may not be true, I just assumed that Rational had the merge alg they use patented but I never actually found a patent for it. No worries, we came up with a much nicer way to do it that I'm positive they do not have patented because their system can't do it.
And that's what the RTAI guys or anyone else would have to do as well. That's why real engineering is so expensive, it's not enough to just build it, you have to build it in a way that hasn't been covered by some patent. The only real way I know to do that cheaply is to be ahead of everyone else. Otherwise you have to do your homework. And at this point, it's virtually impossible to be ahead of everyone else, too much ground has been covered. So you watch the patent database, you think about how other people solve the problems, you do what you can. It's not pleasant. That's way they pay you to do it.
Signature · 2 lines
--- Larry McVoy lm at bitmover.com http://www.bitmover.com/lm